The prior art is replete with examples of power transmissions using variable pulley devices comprising a pair of pulleys connected by a belt. The generally accepted variable pulley transmission for automobile use has a clutch and a forward-reverse-neutral mechanism between the prime mover and the transmission. The rate at which the belt can be shifted diminishes as the pulley speed decreases, and in the usual arrangement when the starting mechanism is located between the motor and the drive pulley, the pulley speed decreases rapidly to zero when the vehicle is brought to a stop. It is desirable to maintain the belt in high ratio over a wide range and steady state vehicle speeds, but if a sudden stop is made from say 20 MPH, it is difficult to return the belt to the starting or low ratio before the pulleys stop rotating. With the usual arrangement, a compromise is made to maintain the belt in lower ratios below about 25 MPH, which adversely affects fuel economy. Also, with the usual arrangement, it is necessary to bring the vehicle and pulleys to a complete stop before engaging reverse gear which reverses the direction of rotation of the pulleys; in such case, it is difficult to rock the vehicle out of snow or mud.